What is your actual goal? If you want to build strength, then for sure get more plates ASAP. If you're training for fat loss and/or muscle, you'll be fine playing with exercise choice, variations, and programming (like the guys have said) and can get more plates whenever.
Going from deadlifting 300x2 to 300x12 isn't losing strength. Deficit deadlifting or snatch-grip deadlifting 245x5 to 300x5 isn't losing strength. Deadlifting 300x5 as the first exercise of the day to deadlifting 300x5 after rows, chin-ups, and dumbbell rows isn't losing strength.